Bulma, and others like it (Milligram is my favourite) have enough functionality to get going: responsive layout/grid, typography, form styling) but they don't have a huge, heavy set of components and requirements like Bootstrap.

I think people really au fait with CSS prefer to add only what they need rather than serve Bootstrap entirely.

> but they don't have a huge, heavy set of components and requirements like Bootstrap.

But that's all optional, Bootstrap is modular [1] [2] [3].

[1] https://getbootstrap.com/docs/3.3/customize/

[2] https://github.com/twbs/bootstrap-sass/blob/master/assets/st...

[3] https://github.com/twbs/bootstrap/blob/v3-dev/less/bootstrap...

> but they don't have a huge, heavy set of components and requirements like Bootstrap

That's a drawback. For BS3 or 4 I can just comment out what I don't need. If I do need many of the components and JS modules that Bootstrap provides OOTB, I have to write them myself. I'm using a CSS framework to avoid doing that.

I've just started using Bulma with Angular. I don't need or want any javascript, but a pure CSS framework, which Bulma is.

Edit: And can be easily customized.